Do we need to unsubscribe HTTP client in Angular?

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As hand washing and social distancing is the major tool for elimination Corona Virus leak, as unsubscribing is the essential tool for avoiding memory leaks when we use Observables. It’s the must thing to do, otherwise, we have unused object references inside our application. But if we use the HTTP client, there is no need to call unsubscribe. Why’s that?

The answer lives inside, how actually Angular creates this observable. If we dig inside Angular source, there is a class called XHRConnection, which is responsible for creating an AJAX request, transform it to Observable and return the response back. Here’s how it’s creation process looks like (don’t read it whole, just take a glance)

The most important piece of code for us is this